Three young girls who were subjected to prolonged sexual, physical and emotional abuse in an island community were repeatedly failed by social work staff who did not listen to them and did not put their interests first.

In a report by inspectors, social workers on the Western Isles were accused yesterday of leaving the vulnerable children in squalid and dangerous conditions with their mother and father - a known and high-risk sex offender - when they should have been taken into care.

In the report from the Social Work Inspection Agency, the authors conclude the children were subject to "prolonged sexual abuse" by both men and women, at least one of whom was not a member of their family. But they do not address police allegations of ritualistic and satanic sex abuse on the island.

It is believed the parents of "Family A" took their children to the Western Isles from England in 1995 to escape the scrutiny of social services. They succeeded. On their arrival on Lewis, the father was wrongly, say inspectors, reclassified as being at a low risk of re-offending. Despite signs of sexual, physical and emotional abuse, the girls were allowed to remain with their parents.

From almost the moment they arrived on the island, the children showed signs of abuse and even told adults about it. But they were ignored. In 1998, when the eldest child was taken into care, the abuse worsened for the two youngest children left at home.

One girl described how she slept in a cupboard, and another said she was so hungry she was forced to eat cat food. One of the girls later told carers her father would receive money for letting other people abuse her. The girls were eventually taken into care in 2001.

The report comes after a huge child protection investigation called Operation Haven on the island and at other locations in England in October 2003. During dawn raids, 13 men and women were arrested and nine were eventually charged with offences, including rape and lewd and libidinous behaviour. But in June last year, the Crown Office said there was insufficient evidence against them and dropped all charges.

Some of the accusations centred on ritualistic sex abuse, including satanic rituals and animal sacrifice. The inspectors said that they had not established that this had taken place. "It was not something we set out to prove. All we can say is that we believe the children were abused by men and women," said Alexis Jay, the chief inspector of social work.

In another family, parents Penny and Ian Campbell were arrested during the raids and their five children were taken into care. Mrs Campbell was released without charge two days later, but her husband was subsequently charged and forced to live away from his children for seven months. There was no suggestion Mr Campbell ever abused any of his own children, and when the Crown dropped charges against him his children were removed from the at-risk register.

"The only connection we had to [Family A] was a council house swap; I have never even met one of the girls," said Mr Campbell. "They may have been abused, I have no idea, but we had nothing to do with it. I believe we were targeted because we are pagans. I can't even hold my child's hand in the street now in case it is taken the wrong way. We want a public inquiry to clear our names."

The three girls arrived on Lewis from England, where they had five social workers assigned to their case, in August 1995.

"Social work managers and practitioners should have acted sooner to protect the children. Some of the decisions that were made were seriously flawed," said the report's authors.

Malcolm Smith, the director of social work in the Western Isles, said the report made "uncomfortable" reading, but added that the girls' case had been "long and complex". Mr Smith said case workers were operating in the wake of the Orkney sex abuse allegations, where social workers were heavily criticised for taking children away from their families, and they were reluctant to make similar mistakes.

The report makes 31 recommendations for improving child protection. Peter Peacock, the Scottish children's minister, has given the authorities in the Western Isles until November 30 to take action.

FAQ Satanism claims

When did the allegations of abuse first come to light?

The oldest child is believed to have been abused in 1990, when she was 14 months old and living in England with her parents. All three children, and their mother, made allegations of abuse throughout the 90s. The family moved to the Western Isles in 1995, where the abuse worsened.

When were the children taken into care?

The oldest child was taken into care in 1998. The other two children were left with their parents because social workers failed to put the needs of the children first. The abuse worsened for the remaining children until they were taken into care in 2001.

Why were dawn raids launched in October 2003?

The girls made allegations to foster carers that they had been subject to sexual assaults from a number of adults. The police arrested 13 people, nine of whom were later charged.

Why were the charges dropped?

In July 2004, the Crown Office announced there was insufficient evidence to meet the burden of proof required in criminal cases.

Is there any evidence of ritualistic abuse?

The report's authors said the children had been abused, including by people outside their family, but would not comment on accusations of satanic rituals.